Modular Chassis Insert for SIG SAUER® P320™

The 80% frame insert for the Sig P320 pistol.

Here it is, folks — the latest and greatest in the world of 80% pistol frames: The MUP-1 Fire Control Group Insert. This is the unfinished firearm component of the modular (and wildly popular) Sig Sauer P320. With this one insert, you can configure a custom P320 from scratch in multiple calibers, frame sizes, and barrel lengths.

Made from high-quality stainless, just like Sig Sauer’s factory frame inserts, the MUP-1 provides incredible tolerances and reliability, with OEM and aftermarket parts compatibility. That means you’ll use all the same pins, springs, chassis, barrels, slides, and other components for the P320 to assemble your finished MUP-1 insert.

80% P320 Frame Insert Specs & Features

• Precision-machined from quality 316 stainless
• Compatible calibers: 9mm, .40 S&W, .357 SIG, .45 ACP
• Compatible Frames: P250, P320, EXO-1 chassis

Other Required Components

• P320 Grip Module
• P320 Lower Parts Kit
• P320 Slide Parts

NOTE: The MUP-1 is an unfinished firearm receiver/frame insert. It is not functional in its current state and cannot be made functional with any components without first being fabricated by you, the end user.

SHIPPING RESTRICTIONS APPLY. Although legal under federal law, the MUP-1 frame insert is not available for sale to certain cities and states.

You must read our shipping restrictions before attempting order. Orders placed by individuals who lived in a restricted state will be cancelled, and a 10% restocking fee may be deducted from your refund.